A new study shows, raising the possibility that the stroke might be the first manifestation of underlying cancer in young stroke patients.
Verhoeven noted that 10% of all stroke cases occur in individuals younger than 50 years. During the past few decades, the incidence of stroke in the young has steadily increased, whereas the incidence of stroke in older adults has stabilized or decreased.
“Stroke in the young differs from stroke in older patients, and one of the major differences is that stroke in the young has a higher proportion of cryptogenic stroke, with no clear cause found in over one-third of patients,” she said.
Also, having an active cancer is known to be a risk factor for thrombosis. This association is strongest in venous thrombosis and has been less well investigated in arterial thrombosis, Verhoeven reported.
Verhoeven’s group aimed to investigate whether in some patients with cryptogenic stroke, this may be the first manifestation of an underlying cancer.
“If this hypothesis is true, then it would be more obvious in young patients who have a higher incidence of cryptogenic stroke,” Verhoeven stated.
They performed a population-based observational cohort study using diagnostic ICD codes from the national Hospital Discharge Registry in the Netherlands and the Dutch Population Registry from 1998 to 2019.
Patients with a history of cancer before their first stroke and those with central nervous system cancers at the time of stroke or non-melanoma skin cancers (which have been shown to have no systemic effects) were excluded.
Reference data came from the Netherlands Comprehensive Cancer Organization, which collects data on all cancer diagnoses in the country. The researchers identified 27,616 young stroke patients (age range, 15 – 49 years; median age, 45 years) and 362,782 older stroke patients (age range, 50 years and older; median age, 76 years).
The cumulative incidence of any cancer at 10 years was 3.7% in the younger group and 8.5% in the older group. The data were compared with matched peers from the general population. The main outcome measures were cumulative incidence of first-ever cancer after stroke (stratified by stroke subtype, age and sex) and standardized incidence rates.
Results showed that the risk for cancer was higher in the younger age group than in the matched general population.
“The younger patients have a higher risk increase of cancer than older patients, and this risk increase is most evident in the first 1 to 2 years after stroke but remains statistically significant for up to 5 to 8 years later,” Verhoeven said.
The cancers that were most involved in this risk increase were those of the lower respiratory tract, hematologic cancers, and gastrointestinal cancers.
The main strength of this study was the use of national databases that allowed for very large sample size, but this brings with it the danger of mis-classification of events and the lack of clinical data, Verhoeven noted. She pointed out that it is not possible to confirm any causal relation from this study design, but a clear association has been shown.
“We need more studies into this field. We need a large clinical data set to examine which clinical phenotypes are associated with possible underlying cancers to identify which patients are most at risk. We are already working on this,” Verhoeven said. “Then it remains to be investigated whether screening for underlying cancer should be added to the diagnostic workup in young stroke patients.”
Parvathy Sukumaran 
